Update mmap-bitvec

Author: Keats

Cargo.toml

@@ -6,11 +6,10 @@ edition = "2018"
 
 [dependencies]
 bincode = "1"
-mmap-bitvec = { git="ssh://git@github.com/onecodex/mmap-bitvec.git", branch="v0.3" }
+mmap-bitvec = { git="ssh://git@github.com/onecodex/mmap-bitvec.git", tag="v0.3.1" }
 murmurhash3 = "0.0.5"
 serde = "1.0.15"
 serde_derive = "1.0.15"
 
 [features]
-marker_lookup = ["mmap-bitvec/rank_lookup"]
 prefetching = []